The present invention is an improvement to methods and apparatus used to pneumatically dispense and distribute loose particulate material. The improvement provides methods and apparatus for applying agents onto loose particulate material carried by an air stream for dispensing and distribution.
A number of industries, including the forest by-products, landscaping, and playground industries have long been in need of efficient methods and apparatus for transporting, dispensing and distributing non-free-flowing or loose particulate materials. An exemplary but non-exclusive list of commonly distributed non-free-flowing or loose particulate materials includes loose bark, wood chips, sawdust, compost, etc. Applications for such materials include residential and commercial landscaping and playground installations.
As society recognizes the increased need to improve the safety of playgrounds, it is increasingly important to cover areas surrounding playground equipment with a cushioning material. Such materials cushion a child""s fall thus reducing the occurrence of injuries. Some of the commonly used playground cushioning materials include loose bark, wood chips, sawdust, rubber particles, etc.
In the past, it had been difficult to safely and efficiently transport and apply loose particulate materials to the application site. Loose particulate materials are generally trucked on site in a dump truck, unloaded and then distributed manually using wheelbarrows, shovels, rakes, etc. To increase the efficiency of the distribution process, the present inventor first invented a container truck to transport and distribute loose particulate materials. The container truck includes an open top through which the truck can be filled using a front-end loader or other loading equipment. The container truck includes a moving floor or conveyor. The moving floor moves loose particulate material within the container into a material feeder at the rear of the container. The material feeder provides a regulated flow of loose particulate material into an air stream from a powerful blower. Loose particulate material exiting the feeder mixes with the air stream from the blower and is blown out of the container through an attached hose. An operator applies loose particulate material by pointing the free end of the hose at the location, where the loose particulate material is desired.
Although the inventor""s first invention dramatically increases the efficiency of the dispensing and distribution process, it had room for further improvements. The moving floor sometimes moves loose particulate material over the feeder so that it xe2x80x9cbridges,xe2x80x9d e.g., blocks the passageway to the feeder, thus preventing material from entering the feeder. An operator must then enter the container truck to break up the loose particulate material so that it falls into the feeder.
In order to prevent bridging or blocking of the feeder, a second operator is located within the container to redistribute or break up the loose particulate material. However, placing an operator within the container is not desirable because the operator is located adjacent to dangerous equipment including the moving floor and feeder. In addition to increasing the possibility of injury, the use of two operators adds to overall distribution costs.
Another concern identified during the operation of the container truck was the production of a great deal of airborne particles. Blowing dry loose particulate materials such as wood chips or sawdust creates a large quantity of airborne particles or dust. The airborne particles create an unpleasant working environment for the operator and people within the vicinity of the application process. In addition, the Environmental Protection Agency (EPA) is investigating whether airborne particles present health concerns for operators or bystanders. The EPA has urged the industry to research methods to distribute dry loose particulate materials without creating large quantities of airborne particles.
Having solved the aforementioned problems in U.S. Pat. No. 5,556,237, the inventor of the present invention has redirected his efforts to another problem. The inventor, having realized that the choice of a proper loose particulate material is heavily influenced by its aesthetic qualities, not the least of which is its colored appearance, has developed a method and apparatus for applying agents onto the loose particulate material cooperatively with the pneumatic dispensing and distributing operation. As a general proposition, consumers prefer dark colors, such as for example, wood chips made from the bark of trees. Unfortunately, much of the wood products which are recycled to make wood mulch or chips do not come from bark, but rather from the lighter tree core. The supply of dark wood is regrettably in short supply. In order to enhance the marketability of the lighter wood products, it is desirable to enhance the aesthetic qualities of the wood chips by dyeing the chips. Rondy (U.S. Pat. No. 5,192,587) for instance, discloses a rotating helical screw conveyer with a reservoir containing a coloring agent in the lower section of the screw conveyer housing. However, devices similar to these further necessitate the loading and transporting of the colored wood chips onto another vehicle for transportation to its ultimate application site. Therefore, the present invention makes use of the dispensing and distributing device to advantageously combine the dyeing operation with the dispensing operation. In addition, the inventor has discovered that virtually any agent which is desirable to be mixed with loose particulate material may be a candidate for this new apparatus and method.
Thus, a need exists in the industry for methods and apparatus to distribute loose particulate materials while enhancing the properties of those materials simultaneously with the distribution and dispensing operation. The present invention is directed towards fulfilling some of these needs.
The present invention is an apparatus and method for applying an agent onto loose particulate material in conjunction with the dispensing and distributing of the loose particulate material. In one embodiment, the apparatus includes a container for holding and transporting the loose particulate material to the site of application. A feeder regulates the flow of loose particulate material out of the container. Loose particulate material exiting the feeder is blown out of the apparatus through a hose by an air stream produced by a blower. In accordance with the present invention, an agent is introduced via a carrier fluid into the air stream carrying the particulate material, whereby the resulting mixture of the agent with the carrier fluid is then mixed with the loose particulate material carried by the air stream.
The introduction of an agent to the air stream carrying the loose particulate material reduces the number of operations required to produce a finished product. Whereas previously, agents such as coloring dyes, fertilizers, fumigants, microorganisms and pesticides have been applied in a distinct and separate operation, unrelated to the dispensing step, the present invention makes use of a carrier fluid to include desirable agents into the dispensing step, thus accruing savings for operators who pass the savings to the consumer.